Gustin has also played Sebastian Smythe on Fox series "Glee", another popular TV show. While his character was recurring on the show, it received positive response from critics and fans.

Gustin was confirmed to play Barry Allen in the second season of "Arrow" on 13 September, 2013. His character was supposed to appear in three episodes, the last one serving as a potential spin-off for "The Flash".

The pilot was picked up with a 13 episodes and premiered on 7 October, 2014. Season 1 of "The Flash" received 4.8 million viewers, the most for a premiere on The CW in five years.

After two weeks, the network confirmed a full season of 23 episodes and the show was renewed on 11 January, 2015, for a second season.

As the 26-year-old actor celebrates his birthday today, check out this rare video of him auditioning for the role of Barry Allen aka the Flash, which catapulted him to fame.